These are the trigonometric functions that you haven’t heard of.
Perhaps sine, cosine, tangent, secant, cosecant and cotangent functions are not enough to make us drive crazy when it comes to learning the basics of trigonometry. There are still 10 more, just a combination of the mentioned six, but is quite useful at times when they will come out in an important exam or you will be randomly asked by your teacher in a recitation.
Source: Wikipedia Commons
What these 10 trigonometric functions can do is to make computations easier by having the most precise values. It can also be never negative.
Versine is more dominant in use with traces back to 400 CE in India. Haversine has been a lot important in recent history though, being used in navigation – it can be used in computing distances between two points on the surface of a sphere using the latitude and longitude of the two points.
In regards to the other functions with “ha” and “co” as prefixes, they only mean “half” and “complementary” of the original.
Sadly, you cannot unsee these trigonometric functions. At least when they turn up in the future, you already have an idea what they are.